Centrifugal pipe casting machine



June 19, 1934. N. F. s. RUSSELL Er Al. 1,963,150

CENTRIFUGAL PIPE CASTING' MACHINE I Filed June 6, 1Q

attouuq Patented June 1.9, 1934` cEN'ramUGAL PIPE ,CASTING MACHINE ANorman F. S. Russell and Frederick C. Langenberg, Edgewater Park, N. J., assignors to United -States Pipe and Foundry Company, Burlington, N. J., a corporation of New Jersey Application June 6, 1933, Serial No, 674,506

`5 claims. "(cl. zz-ss) Our invention relates to-centrifugal pipe casting apparatus and lhas for its object to provide su'ch apparatus with means for building up upon the surface of the cylindrical portion of the centrifugal mold a coating of nely divided dry coating material by means of a carrier gas jet of substantially the entire length of the cylindrical portion of. the mold in advance of the pouring of metal into said co'ated portion of the mold and our invention is particularly, though not exclusively, adapted vfor use lin connection with pipe casting apparatus in which the mold is charged with moltenmetal from a dump trough inserted in and extending over the cylindrical portion of the mold. l o. f,

In our application filed October 19, 1932, Serial Number 638,480, we have described the method of Acoating the cylindrical portion of centrifugalmolds with :tlnely divided dry coating material by means of a jet of carrier gas charged with finely divided dry coating material directed against the cylindrical portion of the mold in such manner as to build up upon said cylindrical surface a coating of the material delivered 'by the' jet and, particularly, the method as applied to that kind of centrifugal pipe casting machine in which the molten metal is delivered to the mold through a relatively retractable runner so as to deliver the metal to the mold in the form of a helix, the carrier gas :let being first directed against one end of the cylindrical portion of the mold in advance of the contact of the molten metal therewith and then as the pouring proceeds, being retracted through the lQngth of the cylindrical portion of the mold at substantially the same speed-with which the runner is Aretracted so as to build up the coating progressively in immediate advance of the contact ofthev molten metal with the` coated portions and in` our said prior` application we have pointed out that the eiliciency of the coating as a retarder of heat transfer is impaired by delay in bringing the molten metal into contact with the coated portion of the mold, due no doubt to the fact that as Vfreshly deposited upon the mold the -coating is made up not only of the particles of dry finely divided material butalso of adsorbed films of gas surrounding the particles which have a -tendency to escape on exposure to the conditions existing in the mold if the coating is not promptly covered by the molten metal. We have also in our said prior application pointed out the desirability of limiting the coating to a thickness not materially in excess of thatwhich will bring about a sufficient retardation of heat transfer to effect the purpose had inview as, for example, the avoidance of areas of chill on lthe ,outer surface of the pipe and we have explained that with highly eflicient coating materials, notably, ferro-silicon applied as a coating by means of the carrier gas jet, we have found it satisfactory to -build up a coating by the distribution over the cylindrical portion of the mold of the dry finely divided material in quantity which, if evenly and compactly distributed over the cylindricalsurface, would form a coating of .0003" in thickness.- We have also in our said prior application pointed out that itis ndt advisable to use in forming the coating, finely divided dryl coating material materially in excess of that which, under the same conditions, would form a coating of .001 in thickness and have explained that among the reasons that it is desirable to limit the thickness of the coating are that byincreased thickness there is increased liability of portions of the coating becoming displaced, 'with the result that portions of the mold are unprotected and, therefore, liable to come in immediate. contact with the molten metal land also that with increased thickness there is increased liability of portions of the coating becoming displaced, with the result that` portions of the mold are unprotected and, therefore, liable to come in immediate contact with themolten metal and also that with increased thickness there /is increased liability for portions of the coating to be displaced by the impact of the molten metal thereupon. The same reasons why the coating should be promptly contacted by the molten metal after it is deposited upon the mold and why the thickness .of the 'coating should not exceed that Iwhich will bring about the desired 'result in the retardation of heat transfer; apply to coatings which are built up upon the cylindrical mold surface by means of the apparatus which' forms the subject matter of our present application.

While, for reasons that we have stated, it vis advisable; that the thickness of the coating deposited upon the lmold should be kept as thin as will make it effective to prevent the formation of a chill, particularly with regard to the quality of the casting produced and While it is true that thicker coatings are more liable to fracture than thinner coatings, We have found that in using the dump trough method of charging a coated mold with molten metal there fis less tendency for the occurrence of fractures and displacement of the coating from the impact of the molten metal than' is the case where the molten metal is supplied through a retracting runner and that in such a methed efeesting itis practical te'use considerably thicker coating than where the metal iS supplied'through a retracting runner.

The leading feature of our present invention lies in the combination with a .centrifugal pipe mold; of a carrier gals jet of such length as, when `in operative position in the moldfto extend over substantially the entire length of`t he cylindrical portion of the mold and so constructed as to deliver a jet of carrier g'as against .an area of the moldextending from end to end of its cylindrical section so'that a relative rotative movement as between the jet and the surface. ef the meld will bring the jet in progressive contact with the surf- V'face to be coated through a progressive series of longitudinal areas. The improved structure also involves the provision of 4means for supporting the jet nozzle in operative position in theniold, preferably retractable with reference 'to the moldI so that the jet nozzle can be inserted and with-v drawn and of means for'supplying theA jet n ozzle with a carrier4 gas and of `means for charging the jet of carrier gas with finely divided dry coating material.

While the nely `divided. dry coating material -may be incorporated. in the j et issuing fromthe jet n'ozzle in'several ways, we consider it advan.v tageous to provide means for chargingthe jet. of carrier gas issuing from'the nozzle with lsaid nely divideddry .coating material after its issue from the nozzle and before the jet comes incon- 1' tac-t with the mold surface and-forths purpose we provide in combination with a jet nozzle and its support an elongated receptacle for-a charge of. nely divided dry coatingl material located in front of the jet nozzle and of such a character as to be adapted to discharge its contents into the jet of carrier' gas from .the nozzle and,

.by preference', we sc locat'e and combine this.

receptacle with the et nozzle that its charge of coating material will lie inthe path of thejet Yissuingfrom the nozzle so as to.be picked ,up and carried frwardby the jet into contact with 't'ure of our-invention. Y While lthese Afea-tures of our `invention which we` have noted-above are capable ofiuse inco'n'-A nection with various devices for supplying molten f the mold surface. This constitutes anothe'lfeametal to Ythe mold,. theyl are especially well adaptedfor usejwith apparatus in which the molten -m'etal is charged into a dump trough extending over the cylindrical portion of the mold' when in place in the mold and discharging its 55. metalwhen tilted 'over -successive areas extending from end to end of. the cylindrical portion ofthe rotating mold'; When'usedin combination withcentrifugal castingapparatus involving the dump "trough, our elongated nozzleand-'freceptale for` coating material', 'if used, are conveniently -sup Y ported on the dumptrough and, where the dump trough; is retractable, withdrawn from and in .combination of our elongated nozzle and recep "tacle for charging material. with apparatusim' pipe" casting. apparatus serted in the mold with the dump "trough, the receptacle of coatingmaterial being, o f couse, 'con-t` veniently charged "at the same time 'while the dump trough is withdrawn from the mold. The.;

volving -a dump trough forms-another'leading.. feature of 'our invention, and our invention. will be best 'understood as described A in connectionwith the drawing in which we have illustrated a involving our novl features and in'which" v`- 'structure supporting the charge Figure 1 isanjelevationpartly in' central len- *l gitdinm section thregh the meld 'et e pipe casting apparatus involving our improvements.

Figure'2 is a cross-section on the line l-2--2 of\ Fig. 1. Figure 3, a 3-3 of Fig. 2. Figure 4, a cross-sectional view generally similar to Fig. -2, but showing a modication in the of' finely' divided .longitudinal section on' the lline dry coating material.

. Figure 5 is an elevation of the ture shown inliig. 4, and

modiedstruc- Figure' is a somewhat diagrammaticucrossg sectional view of another modication in the means -of` charging the 'jet'of-carrier' 'gas with finely divided dry coating material.

A indicates a housing forthe mold which may serve as a water receptacle if water is used as a cooling medium, through which extends' a rotatable metal mold indicated atB, the ends of which extend through the walls of the housing and are supported thereby. C indicates a motor connected 'by gearing, indicated at C1, to rotate the mold. D vindicates acarriage suitably supported on a track, as indicated at D1, to move' longitudinally in alignment 4with the mold. E indicates afdump trough supported on'tlie carriage D and adapted, when itscarriage is moved toward the mold, to extend into the mold.so as to extend over and slightlybeyond the 'cylindrical portion of the mold. F indicates' ahandle lever secured to the end of the dump trough and by means of which'it can bei tilted to discharge its contents. G indicates a countereweig'ht extending from the rear portion of the carriage D'to balance the weight orA the 'charged dumping trough.- H, H, etc.V are brackets securedas shown, to the side .of the dumping trough E, op-

pos'ite to the edge of thetrough over which the f 115 metal is'poured and supporting, as shown in Figs. 1, 2 and 3, a v-shaped'trough I; of suchv length as will, when thefdump trough'is' fully inserted inthe mold, extend over and 'slightly beyond the cylindrical 'port ion of the mold. J isa I 'jet nozzle for a carrier gas, air, for example, which secured to the external apex of the receptacle I and connected with the inside of said receptacleby a series of. holes, indicated at yJ1, .ex

as a`j substantiallyh` approximately even del I and this ca'n be secured by makingthe aggregate l area of the delivery holes J1 considerably less than Vthe crosssec'tional areaof .the nozzle J land, ofcourse, byl a suitableregulation of the deliiryv of gas under Apressin'e tolth'e nozzle'. In'practice we find it' advisable thatth aggregate areaof the outlet openings shouldbelabout one-half of the cross-sectional varea of the nozzle; K is aflexible hose or'rcondit connecting the jet nozzle -.1 -with acsupply tank of thecompressed gas indi-r `cated at K1, and K2 is a regulating 'valve' control'- 'ungftneaelivey ef gas te 'the hose Kane nezzie J'. L indicates-thecharge of coating material.

charge'of finlydivided dry coating -material' which,' as shown, liasa horizontal memberjl- 'K and in'thisconstruction thef holes leading from-O the'rjet nozzle; extend through -the upright' rial so as to direct the jet of carrier gas over and.

parallel to the horizontal member I2.. f

In themodication shown in Fig. 6, the receptacle for the coating material consists of a dump trough, indicated at M, having attached at or near its pouring edge a jet nozzle y perforated with holes :il so as to deliver a jet of the carrier gas toward the side of the mold under the pouring lip of the trough M. In this figure, the trough and the jet nozzleare shown in the positions they occupy when the trough is tilted to begin the delivery of coating material to the jet while wefhave indicated in dotted lines what may be called the normal position of the trough and jet nozzle before the trough is tilted.

In operation and referring first to Figs. 1 to 3,

vthe charge of molten metal is poured into the dump trough E in retracted position, that is, when it is withdrawn from the mold and a measured charge of finely divided drycoating material is evenly distributed through the V-shaped contaner I. Thecarriage is then moved toward the mold until the dump trough and container I extend over and, as showmprtly beyond the cylindrical surface of the mol and the mold is set in rotation. Compressed air or other gas is then delivered from the tank K1 through the hose K and regulating .valve lK2 to the nozzle J and through the holes J1 into the receptacle I, with the result that the nely divided dry coating material is picked up by the jet of carrier gas and deposited upon the cylindrical portion of the r0- tating mold, the deposit being made progressively along areas extending from end to end of this portion of the mold so as to build up a coating of the dry finely divided coating material upon the whole cylindrical surface of the mold and of substantially uniform continuity and thickness. Carrier gas is then cut ofi from the nozzle J by closing the valve K2 and the dump trough E is then rotated as by means of the hand lever F, to deliver its charge to the coated surface of the rotating mold.

The operation of the modified construction shown in Figs. 4 and 5, is practically identical with that described with reference to Figs. 1 to 3, while, with regard to the construction 4shown in Fig. 6, the dump trough for molten metal and the dump trough M are charged and inserted in the mold in the same way but the delivery to the vjet of the finely divided dry coating material is effected by tilting the trough M so as to pour its contents into the jet of carrier gas issuing from the nozzle al It should be understood that where the charged jet is directed against the rotating mold the particles of dry finely divided coating material making up the coating, are held in place partly by adherence and partly by centrifugal force exerted upon them by the rotation of the mold but, with thev thin coatings with which we preferably work, a coating applied by the jet of carriergas will have'suiicient adherence to the wall of the mold and among ,the particles of the dry coating material to hold the coating in place with a fair degree of permanence even when the mold is not in rotation. f'

Itshould also be understood that, for the best results, the pouring of the molten metal on the coated surface of the mold should take place as promptly as possible after the deposit of the coating upon the mold by the jet of carrier gas'.

The method steps described in connection with I the operation of our apparatus, notably, the coating of the entire cylindrical surface of the mold in advance of the pouring of molten metal thereupon, forms the subject of our copending application led June 6, 1933, Serial Number 674,502 and the special construction somewhat diagramm'atically shownin Fig. 6, and described in connection therewith, forms the subject matter of our copending application, filed June 6, 1933, Serial Number 674,503.

Having now described our invention, what we claim as newv and desire to secure by Letters Patent, is:

1. In combination with a centrifugal pipe mold having a cylindrical section, a carrier gas nozzle adapted to extend substantially over the cylindrical portion of the mold and to project a jet of carrier gas against the entire length of said cylindrical section, means for supporting said jet nozzle in operative position, means for vsupplying the jet nozzle with the carrier gas and means for charging the jet of carrier gas issuing from the nozzle with nely divided dry mold coating material.

2. In combination with a centrifugal pipe mold having a cylindricall section, a carrier gas nozzle adapted to extend substantially over the cylindricalportion of the mold and to project a jet of carrier gas against the entire length of said cylindrical section, an elongated receptacle for finely divided dry coating material adapted to extend substantially over the length of the cylindrical portion of the mold and so located withreference to the nozzle that its charge of mold coating material will lie in the path of the jet of carrier gas delivered by the nozzle, means for supporting the jet nozzle and elongated receptacle in operative position in the mold and means for supplying carrier gas to the jet nozzle.

3. In combination with a centrifugal pipe mold having acylindrical'section, anelongated receptacle for dry finely divided mold coating material extending substantially over the entire length of the cylindrical portion of the mold, said receptacle having adjacent to its lowermost portion openings to give passageto a jet of carrier gas, a carrier gas jet nozzle adapted to form and direct against the cylindrical portion of the mold a jet of carrier gas equal to the entire length of said cylindrical portion of the mold and so ceptacl, means for supporting the jet nozzle and i elongated receptacle in operative position in the mold and means for supplying carrier gasto the jet nozzle.

4. In centrifugal pipe casting apparatus comprising a. mold having a cylindrical section, means for rotating the mold, a dump trough for molten metal adapted to extend over the cylindrical portion of the mold and means for supporting the dump trough in operative position in the mold, the combination therewith of a gas jet nozzle `supported on the dump trough and, when the dump trough is in operative position, extending substantially over the entire length of the cylindrical portion of the mold, said gas jet nozzle being adapted to deliver a'jetof carrier gas along the entire-length of the cylindrical portion of, the mold and means for supplying the nozzle with carrier gas and means for charging the jet of carrier gas issuing from the nozzle with finely divided dry coating material.

5. In centrifugal pipe casting apparatus comprising a mold having a cylindrical section, means for rotating the mold, a ldump trough for molten I ,lindrical portionv ofl the mold, an elongated carj metal. adapted tol extend over` the cylindrical rir jet nozzlealso supported bythe dump trough portion of the mold and means -for mipporting `and adapted to .produce an elongated jet of car. the dumpl trough in operative `position in the Iier gas directed into the receptacle for coating mold, the combinationtherewith ot a receptaole Anmterial and of a length substantially equal to 5 for a. charge of dry ely divided mold coating the cylindrical portion of the mold and means- 80 `material supported on the dump trough and exfor supplying the jet nozzle with carrier gas.

-' tending; when, the `dump trough is in operative NORMAN E. vS. RUSSELL. position, substantially -over the length of the .c y- FREDERICK C. LANGENBERG. 

